5 thoughts on “Comments/Critiques/Reviews”

We so enjoyed all of you who joined us for the Continental Cordwood Conference 2015 or CoCoCo/15. Thank you all for making it such an enjoyable and educational event. So many put in many miles to come, many spent a lot of time writing papers for the further advancement of Cordwood Masonry Construction and many gathered fun silent auction items.

I have been studying your directives on cordwood homes! I plan on building one in the upper peninsula of Michigan. I have some questions concerning Insulation and the mortar mix! Have you tried 4″ blue board between the walls versus sawdust? And is it better to add sawdust to the mix?

Four inches of Dow Styrofoam (Blueboard) would work in a double-wall cordwood building. (An inner and an outer cordwood wall with insulation between.) With the more normal single wall, broken up pieces of Styrofoam are difficult to work with, leaving lots of air voids. An inch of Styfofoam is very handy tacked to the moddle of the underside of your plate beam (girt), as it is difficult to get the loose-fill insulation into this detail. The width of this piece is the same as the width of the insulated space of your particular wall. You can actually touch this Styrofoam with your log-ends on the top course, establishing a perfect one-inch mortar joint at the top of the wall panel. For the rest of the wall, use some sort of loose fill insulation, such as sawdust, perlite, etc. Sandy Clidaras, buildiung just north of Montreal, very successfully sprayed in polyurethane foam in his single-wall home. Your second question refers to the mortar mix, I presume. We use screened soaked softwood sawdust as a retarder in our mix to slow the set of the mortar. This prevents mortar shrinkage cracks. You should have several good sawdust options on the U.P. You can also use a commercial cement retarder. By the way, you may be intrested to know that we are trying to organize a cordwood workshop for Traverse City, Michigan, in June 2016. Watch cordwoodmasonry.com for news.

I have your book “Earth-Sheltered Houses” and I really like the look of cordwood masonry. Unfortunately the walls of my house are already up….but I was wondering if I was to cut wood to about an inch long and decorate the walls, what would you recommend as a mortar mixture? Thanks!

Seth: Rob Roy here. Many people have done what you are suggesting. In fact, it is known as cordwood siding. We first saw it about 25 years ago at a restaurant near us. The cook had read one of my earlier cordwood books, and, after hours, he and the owner used their big band saw (the one for cutting steaks) to cut logs down to about an inch thick. I think they glued them to the wooden panels, and it looked quite good. Later, Richard Flatau did something similar at his house, on a stud wall covered with chipboard or plywood. He would fasten the short (1.5-inch pkony log-ends to the wall with screws from the back of the wall into the wooden pieces. Then, he pushed regualr cordwood mortar into the spaces between the phony log-ends, Hey presto: the wall looked just like the adjacent wall, which was genuine cordwood masinry. Since then, people have done some amazingly decorative features in this way, and a Paper was presented at the 2005 Cordwood Conference, but those papers are now out of print. I just looked at the paper, though, and most of the contributors just put the 1″ log-ends on a white wall. It looked like cordwood masonry … but there was no mortar. Fast forward to the 2015 Cordwood Conference, held here at Earthwood last July. Richard and Becky Flatau presented their paper, Reverse Alchemy, about cordwood siding, but, again, they just fastened the little logs to a finished plywood wall, no mortar. However, many people have used mortar, and pictures of their projects appear in both articles cited. If I were to do cordwood siding, I would fasten the log-ends to the plywood or chipboard. Then I would paint on a bonding agent, such as Acryl-60 or DAP bonding agent, to the backboard and the side edges of the log-ends. (I would go 1.5 to 2 inches thick with these phony log-ends.) Then, finally, I would use my pointing knife (or gloved hand) to push regular cordwood mortar mortar off the back of a trowel into the spaces between phony log-ends. Wait a while, then point it. Hope this helps. By the way, the book CoCoCo/15 Collected Papers is available from us at our Books and Media page. 25 good articles, well illustrated. (Even cordwood flooring!)